package com.lyz.dataStructure.sust;

import java.util.Scanner;

/**
 *@Author:759057893@qq.com Lyz
 *@Date: 2019/7/12 15:07
 *@Description:
 **/

/*
求累加和
 */
public class Test10 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()){
            int sum = 0;
            int n =sc.nextInt();
            for(int i=1;i<=n;i++){
                sum +=i;
            }
            System.out.println(sum);
        }
    }
}
